It is a well known fact that an ironing temperature, i.e. the temperature to which an item that is being ironed is heated during the ironing process, is to be chosen in dependence of the type of fabric of the item in order to obtain optimal ironing results. For example, in case the item is made of cotton, the ironing temperature may be relatively high, e.g. around 175° C., whereas when the item to be ironed is made of polyamide or elastane, the ironing temperature should be much lower, e.g. about 95° C., so as to avoid scorching of the item.
Which approximate ironing temperature is to be used for ironing a certain fabric type to obtain optimal ironing results can be found in a variety of publications including encyclopedic and/or instructional internet websites, ironing device user manuals with recommendations from the manufacturers, and patent publications. A further authorative category of publications concerns international standardization norms, including for example ISO 3758 (Textiles—Care labelling code using symbols') from the International Organization for Standardization, and European Standard EN 60311 (‘Electric irons for household or similar use—methods for measuring performance’) originating from the European Committee for Standardization and approved by the European Committee for Electrotechnical Standardization. The ISO standard has introduced textile care markings for maximum ironing temperatures. The textile care labelling of the ISO standard is indicated by one, two and three dots placed within an ironing symbol. The European Standard takes account of the recommendations of the ISO standard, but to obtain improved ironing results the temperatures have been adjusted as shown in the following table:
TABLE 1Soleplate temperatureMarking(° C.)Material, for example• (1 dot) 95 ± 25acetate, elastane, polyamide,polypropylene•• (2 dots)130 ± 30cupro, polyester, silk, triacetate,viscose, wool••• (3 dots)175 ± 35cotton, linenHence, although the precise temperatures may differ, it is generally acknowledged that an item is best ironed at a temperature that corresponds to the nature of the fabric it is made of.
In agreement with this insight, virtually all contemporary domestic (steam) irons come equipped with a heatable soleplate whose temperature is manually adjustable within a range of about 70-210° C. To properly iron a certain fabric with such an iron, the user is expected to be aware of the thermal properties thereof, or at least of the fabric type and/or recommended temperature settings, and to adjust the soleplate temperature of the iron in accordance therewith before he starts to iron the respective textile. Disregarding the recommended soleplate temperature setting may lead to unsatisfactory ironing results, and even thermal damage to the ironed material if the soleplate temperature inadvertently exceeds the maximum recommended temperature.
The need to be aware of the thermal properties of a fabric and to adjust the soleplate temperature of the iron upon changing from one fabric type to another (if the current setting is unsuitable) is considered laborious and user-unfriendly. It appears, however, to be necessitated by the inherently different thermal properties of different textiles.
In an attempt to provide for a more user-friendly iron WO 2008/034693-A1 discloses a steam iron including a heatable iron base, a heating device for heating the iron base, and an integrated automatic temperature control device which is coupled to the heating device and designed to keep the ironing temperature of the iron base exclusively in a fixedly preset, manually nonchangeable, constant ironing temperature range from 180° C. to 190° C. during operation of the steam iron. WO'693 teaches that all textiles, in particular garments and household textiles, that do not include special industry textiles can be ironed within said temperature range with ‘very good’ ironing results. Allegedly, ‘good’ ironing results are still obtained when the items are dry-ironed, i.e. without the application of steam. WO'693 further advises that textiles, which according to EN 60311 have a maximum ironing temperature of 160° C. (i.e. two-dot-textiles, see Table 1), can be steam ironed with ‘good’ results in the said temperature range of 180-190° C.
Tests performed by the applicant of the present application have not been able to confirm the claims made by WO'693. It appears that delicate items are awarded with a one-dot ironing temperature indication in their care labels for a reason. For example, efforts to iron one-dot acrylic garments using an iron at a soleplate temperature of 165° C. (indeed still safely outside the range claimed by WO'693), both with and without the use of steam, have resulted in damage to the garments in the form of permanent stiffening of the textile. In fact, the tests revealed that even two-dot items, such as garments from polyester or wool, are preferably not ironed at this temperature as this is bound to lead to irreversible damage during normal ironing practice. In the case of a partially polyester garment (65% polyester, 35% cotton) the ironing resulted in stiffening of the textile, while in the case of a 100% polyester garment the material was observed to soften and stick to the iron's soleplate. In another test the dry ironing of a woolen garment at a soleplate temperature of 165° C. led to noticeable discoloration. It is expected that the thermal damage observed in these tests would be more pronounced if the soleplate temperature were raised to within the range of 180-190° C. that is recommended by WO'693.
The degree of damage inflicted by an iron with an overheated soleplate may presumably be mitigated by continuously moving the iron across the garment at an exceptionally rapid pace, thereby essentially preventing the transfer of large amounts of heat from the soleplate to a single patch of the fabric. Such ironing behavior, however, is rather tiring and would require the average user to adjust his ironing habits. In a practical sense, the above-described tests thus seem to verify the commonly held belief that an ironing temperature is best chosen in dependence of the type of fabric of the item so as to avoid damage and to obtain satisfactory ironing results.
As the problem addressed by WO'693 is yet unsolved, it is an object of the present invention to provide for an ironing device with which different fabric types can be ironed with satisfactory ironing results, without requiring the user to adapt any ironing settings upon switching from one textile to another.